Disruption of the Urogenital Microbiota following Urogynecologic Surgery

Objectives: Perioperative events could alter the urogenital microbiota (UG). We aim to compare the postoperative UG microbiota to preoperative UG microbiota in premenopausal and postmenopausal women undergoing pelvic floor surgery.

Methods: In this IRB-approved prospective observational study, females undergoing urogynecologic surgery requiring a standard vaginal prep and intraoperative antibiotics were enrolled. Exclusion criteria were self-catheterization, pregnancy, non-native bladder or immunocompromised state. Demographics and clinical data were chart-extracted; participants completed the Pelvic Floor Distress Inventory. This analysis reports on catheterized urine and a vaginal swab collected at 2 time points: 1) day of surgery prior to antibiotic administration and surgical preparation and 2) end of surgery, immediately postoperatively prior to leaving the operating room. Samples were preserved with AssayAssure and stored at -80C. Genomic DNA was extracted with the DNeasy Blood & Tissue kit, the V4 region of the 16S rRNA gene was PCR-amplified, and the amplicons sequenced on a NextSeq2000. Cutadapt quality trimmed raw reads, DADA2 determined amplicon sequence variants, taxonomy determined with SILVA and BLCA with minimum confidence of 70%, and contaminant reads removed using decontam. Within-participant change in UG microbiota was assessed using Wilcoxon signed rank and McNemar’s tests for alpha diversity and single genus predominance, respectively.

Results: Twenty premenopausal and 20 postmenopausal subjects were included. Clinical and demographic information was similar between premenopausal and postmenopausal women, except for age and stage of prolapse (Table 1). Most catheterized urine samples with single genus predominance preoperatively were predominated by Lactobacillus (59%), followed by Gardnerella (13%). In the aggregate, each measure of alpha (within-patient) diversity increased significantly (p£0.01 for all comparisons). There was a corresponding loss of single genus predominance (often Lactobacillus) in both the bladder (p < 0.001) and vaginal samples (p=0.007) (Table 2). These results reflect a marked disruption of the microbiomes of both niches in a cohort of premenopausal and postmenopausal women. Alpha diversity was higher in postmenopausal vs premenopausal at both time points (p < 0.001).

Conclusions: The UG microbiota experienced significant compositional change following urogynecological surgery, as reflected by increased diversity and loss of single genus predominance. The loss of protective bacteria, especially Lactobacillus, may provide opportunity for lower urinary tract infections that are prevalent after surgery. Postmenopausal women may be particularly susceptible due to higher diversity at both time points.